An Illinois man who worked as a spokesman for a leading "darknet" marketplace that users accessed anonymously to buy and sell illicit goods pleaded guilty Thursday to a federal conspiracy charge in Atlanta.

Ronald L. Wheeler III of Streamwood, Illinois, worked for about two years as a public relations specialist for AlphaBay, which authorities have said was the world's leading darknet marketplace until it was taken down through an international law enforcement effort in July. People used it to trade in illegal drugs, guns, counterfeit goods and hacking tools, among other things.

Wheeler worked with others to steal personal information -- including passwords, email addresses and bank account numbers -- to obtain money, goods and services, prosecutors said in a court filing.

Wheeler, known online as Trappy and Trappy_Pandora, began working as AlphaBay's public relations specialist in May 2015. His duties included moderating the AlphaBay forum on Reddit and posting information about AlphaBay in other Reddit forums, mediating sales disputes among the marketplace's users, providing nontechnical assistance to users and promoting AlphaBay online, Assistant U.S. Attorney Samir Kaushal told the judge.

"Wheeler spent hours on the Dark Web and general Internet providing AlphaBay users tips for attempting to avoid detection by law enforcement," U.S. Attorney Byung J. "BJay" Pak said in a news release.

One of Wheeler's duties was to let AlphaBay users know when the site would be down for maintenance. That was important, Kaushal said, because it was necessary to reassure users that the site hadn't been taken down by law enforcement or otherwise compromised.

Wheeler was paid a salary in bitcoin, a digital currency, by Alexandre Cazes, the 25-year-old Canadian owner of AlphaBay who was known online as Alpha02 and Admin, the court filing says.

AlphaBay used Tor, a network of thousands of computers run by volunteers, to hide its tracks. With Tor, traffic gets relayed through multiple computers, with identifying information stripped at each stop so no single computer knows the full chain.

"If people think the Dark Web gives them autonomy to operate illegally behind a cyber-curtain without the scrutiny of law enforcement, then Mr. Wheeler's plea is a stark reminder that we won't let that happen," Special Agent David J. LeValley, who heads the FBI's Atlanta office, said in the release.

The court filing says Wheeler's work with AlphaBay ended July 3, 2017. Two days later, Cazes was arrested in Thailand with DEA and FBI assistance, with AlphaBay going offline. Cazes died in Thai police custody on July 12. The country's narcotics police chief told reporters at the time that Cazes hanged himself in jail just prior to a scheduled court hearing.

The police agency Europol estimates AlphaBay had done $1 billion in business since its 2014 creation. Cazes had amassed a $23 million fortune as the site's creator and administrator, according to court documents.

As part of a plea deal reached with prosecutors, Wheeler agreed to forfeit $27,562 in cash found in his home and 13.97 bitcoins, Kaushal said. Wheeler has also been cooperating with investigators.

U.S. District Judge Leigh Martin May accepted the 24-year-old Wheeler's guilty plea and set sentencing for May 24. Wheeler faces up to five years in prison and a fine of up to $250,000.